Bit clamp



C. P. BROWN BIT CLAMP Filed April 6, 1922 n n mw J wwe v wV/ 957/49 awa Patented May 15, 1923.

COMMODORE P. BROWN, OF BONCEVERTE, WEST VIRGINIA.

BIT CLAMP.

Application filed April 6, 1922. Serial No. 550,193.

To all whom it may concern:

Be it known that I, COMMODORE P. BROWN, a citizen of the United States, residing at Ronceverte, in the county of Greenbrier and State of West Virginia, have invented new and useful Improvements in Bit Clamps, of which the following is a specification.

The invention relates particularly to quick acting bit clamps of that type employed with a brace of the hand'operated type as used by carpenters, but it will readily be apparent that the subject matter of the device may be usedin connection with other tools of this character. object of the invention is the provision of means involving certain combinations and arrangements of parts of the bit stock or shank and clamping sleeve whereby the bit may with facility and convenience be clamped in operative position for use, or may'with equal facility be released and detached as required, and whereby-the bit may be firmly and securely held for drilling or boring purposes.

In the accompanying drawings I have illustrated one complete example of the physical embodiment ofmy invention, wherein the parts are combined and arranged according to the best mode I have thus far devised for the practical applica tion of the principles of my invention.

Figure 1 is a vertical sectional view through the bit stock, showing the clamp ing means for the bit, and showing also the relation of the brace stock thereto.

' Figure 2 is a view in elevation of the bit stock, with the bit removed, and showing one of the clamp jaws.

Flgure 3 is a transverse sectional view at line 33 of Figure 1.

Figure 4 is a transverse sectional view at line 4-4 of Figure 1.

In the preferred form of my invention as shown in the drawings I have illustrated a portion 1 of a brace stock fashioned with the usual socket 2, and the bit stock or hollow shank 3 is provided with the usual ratchet head 4 within the socket 2. A. standard form of pawl is carried by the brace stock for engagement with the ratchet head of the bit stock, and a securing screw 5 holds the brace stock and the bit stock in correct operative relationship.

The device is manipulated in usual manner for boring or drilling with hand tools,

The primary and the shoulder or collar 6 on the bit stock or shank forms a stable joint between the brace stock and the bit stock as usual. At its lower end the bit stock is fashioned with a transversely extending slot 7, in which are located a pair of opposed clamp jaws 8 and 9, having at their lower ends, exterior cam faces .8 and 9. At their upper ends these jaws are provided with complementary, inwardly extending bosses 10, projecting into the interior space 11 of the slot 7 of the bit stock, and shoulders 99* are also formed on the jaws intermediate their lower ends and the bosses.

The bit 12, which may form'one of a usual set oftools of this type, is fitted into the bit stock with its angular tang 13 seated in the socket 14 of the bit stock the socket member being shown integral with the slotted bit stockand located betweenthe two jaws 8 and 9 and just below the transverse slot 7. The socket member thus forms an obstruction or suspension device co-acting with the two bosses 10 and the shoulders9 of the jaws to prevent dislocation of the jaws when enclosed by the sleeve 15.

The bit stock is encased with this gripping or clamping sle'eve'15 which is'of the usual barrel shape and is fashioned With interior screw threads 16 at its upper end. At its lower end the sleeve is provided with an annular flange 17 to engage the cam faces 8 and 9 of the jaws 8 and 9. I 7

At its lower end the bit stock is exteriorly threaded as at 18, over which threads the complementary threads 16 of the sleeve are turned when positioning the sleeve on I the bit stock, and these threads-18, it will be apparent, also prevent the sleeve from slipping off the bit stock when not other wise secured thereto. Q

The upper, interiorly'threaded end of the sleeve is adapted to engage a pair of dogs 19 and 20 which have screw threads 21 at their opposite outer faces, and these dogs are located inv a transverse slot 22 in the bit stock, just below the collar 6-thereof. The dogs are pivoted on a pin 23 extending centrally and transversely through the slotted bit stock, the dogs being cut away to overlap as shown in Figures 1 and 3.

Above the pivot pin, each dog is fashioned with an end lug 24:, and between these lugs a distending spring 25 is interposed, which tends to force the lugs 24 outwardly from the pivot pin and to retract the threaded edges 21 of the dogs from engagement with the threads 16 of the clamp sleeve.

The lugs are fashioned with curved outer faces toco-act with. a cam ring 26, and the latter is provided with'inner opposed cam faces 27 in frictional contactwith the lugs.

Thus it will beseen in Figure that if the earn ring is turned to the right or clockwise the lugs are free to be distended or pressed outwardly by the spring 25. [This action of the spring causes the dogs to swing on their common pivot resulting in the disengage ment of the threads of the dogs from the in- 'terior threads of the clamp sleeve, thus tree ingthe sleeve from the 'bit stock. The sleeve is now freeto fall or be withdrawn from the bit stock, disengaging the clamp ring or shoulder 17 from. the cam faces 8 9 0f the jaws 8 and 9, and then the tang of the bit may be withdrawn fromthe bit stock. I

In fitting the bit to its stock, the tang 13 is pushed into its socket 14, between the jaws 8 ends, the dangling sleeve is turned on the interrupted threads 18 of the bit stock until the former is released from the latter'and then the sleeveis slipped up- -warclly to its position in Figure 1 to engage vthe'threaded edges of the dogs. The dogs areheld in the slotted bit stock in order lthat the sleevemay be screwed thereon, and

this action, which is an upward and rotary movement of the sleeve, results in closing the jaws on the bit and locking the" sleeve on 'the bit stock. The cam ring 24L is prevented from dropping off the bit stock by means of the protruding ends of the pivot pin 23,

i From the above it will'be apparent that by turning the cam ring 26 as described, the clamping sleeve may be quickly released from locked position, and that the bit may thenwith facility andconvenience "be withdrawn or detached from its stock,

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is i 1. A bit clamp comprising a bit stock'and clamping jaws car'riedthereby, a clamping sleeve for the jaws having interior threads, a pair of pivotally mounted dogs having complementary exterior threads to engage the sleeve to hold said sleeve. against sliding movement andpermitting rotary movement,

a cam ring surrounding saidstock and adapted to force the threads of the dogs into engagement with the threaded sleeve,

and means engaging the dogs Ito disengage the latter from the sleeve when the dogs are released by the cam ring 2. The combination with a bit stock and clamping jaws carried thereby, of a clamping sleeve having interior threads, and a pair of -pivotally mounted dogs having comp'lementary exterior threads, lugs fashioned at the inner ends of said dogs, a cam-ring surrounding'said bit stock adapted to co-operate witlrsaid lugs to move the threaded 'dogs' 'in'to engagement with the sleeve when rotated in one direction; and release the dogswhen rotated in the opposite direction, v

and a spring positioned between said lugs to swing the dogs out of engagement with the sleeve when the lugs are released.

3. In a bit clamp, the combination with a.

bitstock, clampingvjaws carried thereby and a clamping sleeve for said'jaws, of a' spring pressed dog pivoted in the" bit stock, complementa-ry threads on said sleeve and dog,

a rotatable ring mounted on the bit'stock, and a cam face on saidring adapted to co act with the dog to engage the latter with said sleeve.

ooMMoDfonE r..;B-noWN. 

